understanding macd

Deep understanding of shallow copy and deep copy in python, and deep understanding of python copy Before talking about what is a copy of depth, let's look at this phenomenon: a = ['scolia', 123, [], ]b = a[:]b[2].append(666)print aprint b Why does it affect a if I only modify B? I have read it in my previous article and said: memory references are stored in the sequence. Therefore, when we modify the empt

A deep understanding of the java garbage collection mechanism and a deep understanding of garbage collectionAn in-depth understanding of java garbage collection mechanism-I. Significance of the Mechanism A notable feature of Java is the introduction of the garbage collection mechanism, which helps c ++ programmers solve the most troublesome memory management prob

A preliminary understanding of javascript object-oriented, a preliminary understanding of javascript Preface Class-based objects: we all know that object-oriented languages have an obvious sign that they all have the concept of classes, you can create many objects with the same attributes and methods through the class-like template. However, ECMAScript does not have the concept of a class. Naturally, it is

Deep understanding of html5 tags and deep understanding of html5 tags Introduction: I believe everyone is familiar with html5, but what is its true significance in specific development? What new definition and concept does html have? Why do some experts believe that after html5 is fully completed, all work can be achieved in the real cloud mode? Have you understood this series of questions? This series of a

Deep understanding of jQuery event processing and deep understanding of jquery events Browser event model DOM level 0th event model 1. Event instance This attribute provides a large amount of information about the currently being processed trigger events. This includes some details, such as the event triggered on which element, the coordinates of the mouse event, and the key clicked in the keyboard event. 2

parent class, but it is helpless for the methods defined in the Child class but not in the parent class; At the same time, a method in the parent class can be referenced and called by the parent class only when it is defined in the parent class but not overwritten in the subclass; Understanding of polymorphism: polymorphism is embodied in inheritance, so there must be an inheritance relationship. Then the subclass must override the parent class met

Computer Register Controller Operating System Development History Ma GE has talked a lot about it and can understand it, but I need to remember a few things. However, I still drew a picture based on my understanding of the computer, which is not necessarily accurate, but it is similar, 650) This. width = 650; "src =" http://s3.51cto.com/wyfs02/M01/4C/C5/wKiom1RFKb6wWpPNAAFOeh1h9wo313.jpg "Title =" Rabbit .png "alt =" wkiom1rfkb6wwppnaafoeh1h9wo313.jpg

kinds of elements have different grammatical meanings and constituent rules, they cooperate with each other and accomplish the semantic expression of the Java language together.A week of learning to understand the download and configuration of the JDK, a simple grasp of the use of the Javac,java command. Through the gradual in-depth study, we will learn in detail the five elements of Java, and its use, with mathematics and other related knowledge to solve the problem of the algorithm and so on.

Writer:bysocket (mud and brick pulp carpenter)Weibo: BysocketWatercress: BysocketMason first met Navicat is a hashcode method in the Java.lang.Object source code: 1 public native int hashCode(); Why is there a navicat? This is the place where I want to study. So today Masons want to summarize the next navicat.First, the understanding native namely Jni,java native InterfaceAll a language, all hope is pure. For example, t

object? The answer is yes, because the local object can be thought of as a derived type of function, in this sense, They can be equated with user-defined functions. (Echoes the "Built-in data types" section of the Understanding javascript_04_ data Model) var obj=new Object (); is to create the instantiated object obj using the built-in object. var obj={}; and Var obj=[]; This code will trigger the construction of object and array by the JS engine. fu

Understanding and understanding of pointers Int main (void) { Int;Int * p; int ** p1; a = 5; p = a; p1 = p; printf ("\ n "); printf ("the address of a is % p \ n", a); printf ("the value of p is % p and the adress of p is % p \ n ", p, p); printf ("the value of p1 is % p and the address of p1 is % p \ n", p1, p1 ); printf ("\ n"); printf ("a's value is % d \ n", ); printf ("a's value is % d access by f

In-depth understanding of C pointer 2: C memory management, deep understanding of Memory Management 　　Memory ManagementIt is important for all programs. Sometimes the memory is implicitly managed by the runtime system, such as automatically allocating memory for variables. In this case, the variable is allocated to the stack frame of the function in which it is located (each function has its own stack frame

Deep understanding and application of Float attributes, deep understanding of float attributesI. Features of Float 1. Applied to text-centered Images 2. Create a block-level box 3. Multi-column floating Layout 4. The width and height of the floating element are adaptive, but the value can be set.Ii. Core Issues Text surrounding image: img labels and multiple text labels are placed in one container. If img i

Understanding about Cache Usage and understanding about Cache Usage First of all, the advantage of caching is that the cache stores data in the memory and extracts the data from the memory when needed (compared with the data obtained from the hard disk, the cache speed is much faster) prompt speed Cache category: Page cache data source cache (permanent and time-limited) Dependency items cache database depe

Basic understanding 2: CSS3 button animation, understanding css3 button Animation A Css3 button works very well. after reading it carefully, we found that: after,: before is followed by transition, transform, and other effects. Focus on the following points for easy implementation: 1. position is required for the pseudo class, and positioning is required for the relative button. 2. Set the z-index attribute

2. in-depth understanding of floating and positioning, and in-depth understanding of floating PositioningFloating and positioning 1. There are several notes on absolute positioning: 1) absolute positioning is used to offset an "existing" ancestor element "of its" nearest. If no ancestor element has been located, the browser window is used as the benchmark for offset; 2) If the parent element is not posit

A deep understanding of the synchronous and asynchronous mechanisms in JavaScript programming and a deep understanding of javascript One of the advantages of JavaScript is how it handles asynchronous code. Asynchronous code will be put into an event queue and will not block the thread until all other code is executed. However, it may be difficult for beginners to write asynchronous code. In this article, I

A deep understanding of Spring transaction principles and a deep understanding of springI. Basic principles of transactions The essence of Spring transactions is the database's support for transactions. Without the database's support for transactions, spring cannot provide transaction functions. To use transactions to operate databases only using JDBC, follow these steps: With the Spring transaction managem

A deep understanding of javascript variable declaration and a deep understanding of javascript Compared with C/C ++, The for loop in ECMAScript cannot create a local context. Copy codeThe Code is as follows:For (var k in {a: 1, B: 2 }){Alert (k );} Alert (k); // although the loop has ended, the variable k is still in the current scopeVariables can only be declared by using the var keyword at any time.The ab

Understanding the prototype and prototype chain in javascript, understanding the prototype of javascript Prototype As we all know, JavaScript does not contain the traditional class inheritance model, but uses the prototype model. Code implementation is like this. function Student(name){ this.name = name;} var Kimy = new Student("Kimy"); Student.prototype.say = function(){ console.log(this.name + "say");}Ki